Passenger vehicles, light trucks and heavy duty trucks may in some examples include an ability to support 110V-120V alternating current (AC) and 220V-240V AC electrical loads. As an example, such vehicles may support electrical loads up to around 450 Watts, and in the future may support electrical loads from 2KW-8KW and potentially higher (e.g. 16KW and greater). Systems for such vehicles may include designs for directly supporting such appliances either while the vehicle is stationary, for example for use at a job site or for supplying electricity to home electrical loads, or while the vehicle is moving, for example to power a refrigeration unit. Such systems may comprise direct current (DC) to AC systems, and may be referred to as a power to the box (PttB) system. Such PttB systems may be driven either by an alternator, a belt-integrated starter generator (BISG) driven by the engine or by a high voltage battery (e.g. 300V-350V) which is in turn charged by a crank ISG (CISG).
In cases where a PttB system is in operation to power external electrical load(s) and where the vehicle is moving, it may be expected that air in an intake manifold of the engine is either fresh air, or if the vehicle is operating with exhaust gas recirculation (EGR), the EGR mass is measured and accounted for in the fresh air mass calculation. However, there may be circumstances where the PttB system is being utilized under conditions where vehicle exhaust external to the vehicle may build to a level where unmetered EGR is ingested into the engine. As an example, if the vehicle is being operated in PttB mode in a situation where exhaust gas is not routed away from the vicinity of the vehicle but instead builds in concentration over time, such a situation may effectively increase the level of (e.g. concentration of) exhaust gas of air in the vicinity of the vehicle. A rate of such an increase may be a function of at least initial air mass in a volume of space where the level of exhaust gas in the air in the vicinity of the vehicle is increasing, vehicle exhaust mass flow rate, and any sources of air exchange for the particular volume of space where the level of exhaust gas in the air is increasing.
As percent EGR increases for a gasoline engine for a particular timing of spark provided to engine cylinder(s), burn duration for the combustion of air and fuel may increase as well. Such an increase in burn duration initially may lead to a reduction in net cylinder torque, while at higher levels (e.g. greater than 10% EGR) combustion stability for the engine may become degraded which may lead to incomplete combustion and/or misfires. At even higher levels (e.g. greater than 20% EGR), a reduction in delivered crankshaft torque may result.
To mitigate such undesirable aspects that may result as a function of increasing EGR inducted to engine cylinders, engine control strategy may rely on spark timing advance to engine cylinders to compensate for increased burn duration, which may maintain crankshaft torque at desired levels. However, as the level of EGR being inducted to engine cylinders increases beyond a particular level (e.g. 20%), issues related to combustion stability may result even with increases in spark advance. At higher levels still, engine hesitation and/or stall may result, which may compromise the ability of the engine to support the PttB electrical load.
The inventors herein have recognized the above-mentioned issues, and have herein developed systems and methods to at least partially address them. In one example, a method comprises via a controller, detecting that a vehicle is in a condition of reduced air exchange, and in response to a request to operate an engine of the vehicle to power one or more loads external to the vehicle while the vehicle is stationary, generating an alert pertaining to the condition of reduced air exchange, and discontinuing engine operation if a response to the alert is not received from a vehicle operator within a threshold duration. The condition of reduced air exchange may include the vehicle being in a location in which operation of the engine leads to an increase in a concentration of exhaust gas in air surrounding the vehicle over time.
As an example, detecting that the vehicle is in the condition of reduced air exchange includes an indication of a loss of communication with a threshold number of GPS satellites. In another example, detecting that the vehicle is in the condition of reduced air exchange may be based on information pertaining to driving routes that are learned over time and stored at the controller. In other examples, one or more of vehicle-to-vehicle (V2V) and/or vehicle-to-infrastructures (V2I) communications may be relied upon for such detection.
In response to the response to the alert being received from the vehicle operator within the threshold duration, the engine may be operated to power the one or more loads external to the vehicle. Then, an increase in exhaust gas being inducted into the engine by way of an air intake passage to the engine while the engine is in operation may be monitored. In response to the increase in exhaust gas being inducted into the engine reaching a first threshold, the method may include notifying the vehicle operator that operation will be discontinued if action is not taken to mitigate the condition of reduced air exchange. In response to the increase in exhaust gas being inducted into the engine reaching a second threshold that is greater than the first threshold, the method may include discontinuing operation of the engine.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.